PROJECT SUMMARY/ABSTRACT Project 2 ? Opioid Treatment for Pain: Causes and Consequences Pain is arguably the most prevalent and most expensive public health condition in the U.S., and assessment and treatment of pain have emerged as markers of high-quality health care. Yet one common treatment? opioid pain medication?itself carries serious health risks, including increased pain sensitivity, dependence, and addiction. Opioid use, misuse, and abuse have skyrocketed in the the past two decades, creating a major public health crisis. This crisis has revealed the lack of research evidence to guide health care providers on the appropriate management of chronic pain and the safe prescribing of opioid analgesics. Pain is vastly under- studied compared to other priority conditions such as heart disease, cancer, and dementia, and even less is known about effective pain management in middle-aged and older adults. Using descriptive and quasi-experimental methods, our goal is to understand why opioid use has risen and how this increased use has affected the health and functional outcomes of middle-aged and older Americans. We will use longitudinal survey data and very large administrative medical claims databases that contain detailed information about opioid treatment among commercially insured, publicly insured, and uninsured patients, and which also include information about physicians and their prescribing behavior. Our first Aim is to understand the initiation and use of opioid treatment for pain by different types of patients over time and across geographic regions, with a special focus on the pathways by which individuals progress from short-term opioid use to long-term opioid use. Our second Aim is to identify factors influencing physician prescribing of opioid pain medications, and to measure the concentration of opioid prescribing among physicians by geographic area. Our third Aim is to evaluate how state and federal policies, along with physician prescribing behavior, have affected opioid use, health, and functional outcomes. This project will contribute to the program project's overall goal of understanding trends in population health, with emphasis on how health care providers and public policies shape those trends to improve the health of an aging population.